add angle angle2 angledVector angleTo angleTo2 crossProduct distanceToVector dotProduct get isCodirectionalTo isCodirectionalTo isDegenerate isEqualTo isLeftOf isOppositeTo isOppositeTo isParallelTo isParallelTo isPerpendicularTo isPerpendicularTo isRightOf isUnitVector isZeroVector kIdentity kXAxis kYAxis length lengthSquare negate normalize operator!= operator* operator* operator* operator* operator* operator*= operator*= operator+ operator+= operator- operator- operator-= operator/ operator/ operator/= operator== perpVector projectResolveVector projectScaleToVector resolveVector resolveVector scaleBy scaleBy scaledVector set set setAngleLength setLength subtract transform unitVector Vector2d Vector2d Vector2d x y

projectResolveVector() float Vector2d::projectResolveVector ( const Vector2d &  xAxis, Vector2d &  proj, Vector2d &  perp  ) const 求本矢量在矢量xAxis上的投影矢量和垂直矢量 将本矢量投影到xAxis，计算投影比例， 正投影矢量 = xAxis * 投影比例，本矢量 = proj + perp 参数 [in] xAxis 投影到的矢量 [out] proj 正投影矢量 [out] perp 垂直投影矢量 返回 投影比例，有正负 函数调用图: 这是这个函数的调用关系图: